Taste solution acceptance is a complex behavior that can be easily measured. Abnormal taste solution acceptance can be due to the disruption of taste perception or altered neural or physiological processes. This is a proposal to refine existing methods of assessing taste solution acceptance so they can be used to screen large numbers of mice. There are three specific aims. The first involves fine-tuning long-term, two-bottle choice tests. A comparison will be made between taste solution intakes of groups of C57BL/6J and 129/SvJ mice during systematic manipulations of drinking bottle spout position, the number of drinking bottles, the test duration, the maintenance diet, and the subjects' age. Additional studies will determine which taste solutions produce carry-over effects (that is, the influence of a solution ingested in one test on solution intake in subsequent tests) and explore procedures to eliminate them. The second specific aim involves optimization of the brief-exposure or "lickometer" test. The proposed studies will establish appropriate solution concentrations and test conditions to optimize the likelihood of discovering mice with aberrant taste phenotypes. The final specific aim involves establishing reference data for the subsequent identification of mice with aberrant taste phenotypes. Normative data will be provided by testing large numbers of C57BL/6J and 129/SvJ mice according to the procedures established in the previous aims. Smaller groups of mice of other strains, including those with known abnormalities of taste solution acceptance, will also be screened in order to illustrate how the tests discriminate among mice with taste perception deficits. A section of the proposal is devoted to administrative issues, including the procedures to be used to disseminate test methods and results. This involves developing a detailed training manual, publishing a database of results, and exploring other ways of providing methods and reference data to interested parties.